In the recovery of oil from oil-containing formations, it is usually possible to recover only minor portions of the original oil-in-place by so-called primary recovery methods which utilize only natural forces. To increase the recovery of oil a variety of supplementary recovery techniques are employed. These techniques include waterflooding, miscible flooding, thermal recovery, and steam flooding.
A problem that arises in various flooding processes is that different strata or zones in the reservoir often possess different permeabilities. Thus, displacing fluids enter high permeability or "thief" zones in preference to zones of lower permeability. Significant quantities of oil may be left in zones of lower permeability. To circumvent this difficulty the technique of profile control is applied to plug the high permeability zones with polymeric gels and thus divert the displacing fluid into the low permeability, oil rich zones. Among the polymers examined for improving waterflood conformance are metal cross-linked polysaccharides, metal cross-linked polyacrylamides, and organic cross-linked polyacrylamides.
Another problem that arises when steam flooding a formation having a non-aquifer bottom water zone is that on occasion steam channels into the bottom water zone. This bottom water zone has relatively high permeability which allows high steam and water mobility therethrough. It is difficult to re-direct the steam into upper portions of the reservoir or formation since steam prefers the path of least resistance. The path of least resistance in this situation happens to be the bottom water zone.
Therefore, what is needed is a method for preventing steam channelling in a bottom water zone which will allow steam to be re-directed into an upper zone of a reservoir so that hydrocarbonaceous fluids can be removed therefrom.